Table 2. Observed Chemical Composition of Air Masses Sampled at 6-12 kma


	Background	EOF 1: Lower Stratosphere	EOF 2: Convection and Lightning	EOF 3: Asian	Biomass Burning
Number of 1-min measurements	2580	243	482	255	73
O3, ppbv	73 +/- 17 (75)	212 +/- 85 (92)	78 +/- 20 (80)	99 +/- 20 (83)	74 +/- 19 (68)
CO, ppbv	95 +/- 15 (94)	80 +/- 23 (92)	103 +/- 18 (92)	128 +/- 14 (106)	255 +/- 154 (130)
H2O, ppmv	719 +/- 880	89 +/- 101	231 +/- 181	527 +/- 428	419 +/- 345
Relative humidity, %	49 +/- 27	24 +/- 20	60 +/- 24	52 +/- 25	34 +/- 12
NOx,b pptv	290 +/- 220 (210)	330 +/- 180 (140)	1040 +/- 600 (437)	290 +/- 200 (130)	230 +/- 160 (67)
PAN, pptv	300 +/- 160 (296)	280 +/- 150 (183)	400 +/- 220 (262)	590 +/- 160 (275)	1030 +/- 650 (281)
SigmaPNs,c pptv	300 +/- 190	340 +/- 220	390 +/- 290	490 +/- 190	1190 +/- 840
HNO3, pptv	250 +/- 210 (416)	680 +/- 340 (294)	210 +/- 180 (435)	360 +/- 300 (279)	370 +/- 230 (128)
HNO4, pptv	55 +/- 35	85 +/- 35	65 +/- 35	85 +/- 45	85 +/- 40
NOy,d pptv	880 +/- 440 (963)	1370 +/- 360 (624)	1710 +/- 870 (1019)	1330 +/- 460 (527)	1710 +/- 830 (476)
NOx/HNO3, pptv/pptv	0.38 +/- 0.32 (0.50)	0.26 +/- 0.21 (0.48)	1.26 +/- 0.93 (1.00)	0.30 +/- 0.24 (0.47)	0.29 +/- 0.34 (0.52)
SO2, pptv	35 +/- 45 (17)	35 +/- 25 (27)	50 +/- 85 (15)	40 +/- 25 (18)	20 +/- 10 (30)
HCN, pptv	290 +/- 70	310 +/- 90	300 +/- 80	420 +/- 60	1090 +/- 850
CH3CN, ppptv	150 +/- 20	150 +/- 30	150 +/- 20	160 +/- 30	550 +/- 400
CH3OOH, pptv	220 +/- 150	100 +/- 40	200 +/- 180	160 +/- 100	510 +/- 440
H2O2, pptv	510 +/- 430 (480)	120 +/- 110 (218)	160 +/- 130 (255)	580 +/- 420 (468)	970 +/- 680 (808)
HCHO, pptv	240 +/- 310 (179)	230 +/- 410 (78)	250 +/- 230 (206)	180 +/- 190 (134)	420 +/- 370 (105)
OH, pptv	0.29 +/- 0.14 (0.62)	0.35 +/- 0.10 (0.36)	0.47 +/- 0.17 (0.80)	0.26 +/- 0.08 (0.43)	0.18 +/- 0.10 (0.21)
HO2, pptv	9.1 +/- 3.6 (12.5)	5.7 +/- 1.5 (7.5)	6.8 +/- 2.5 (6.7)	9.5 +/- 3.0 (10.7)	13.1 +/- 4.0 (10.5)
C2H6, pptv	720 +/- 270 (637)	540 +/- 200 (719)	980 +/- 510 (628)	880 +/- 190 (844)	1300 +/- 1030 (832)
C2H4, pptv	3 +/- 7	2 +/- 3	6 +/- 7	7 +/- 34	350 +/- 780
C2H2, pptv	80 +/- 30	80 +/- 40	100 +/- 40	160 +/- 40	350 +/- 440
C3H8, pptv	140 +/- 120 (114)	80 +/- 50 (101)	280 +/- 270 (116)	150 +/- 100 (145)	250  +/- 250 (89)
C6H6, pptv	13 +/- 7	9 +/- 5	14 +/- 10	24 +/- 11	130 +/- 263
Toluene (C6H5CH3), pptv	5 +/- 2	NAe	8 +/- 3	5 +/- 2	53 +/- 16
Acetaldehyde (CH3CHO), pptv	100 +/- 70	120 +/- 60	110 +/- 80	110 +/- 50	310 +/- 330
Acetone (C3H6O), ppbv	1.46 +/- 0.85 (0.88)	1.04 +/- 0.69 (0.60)	1.61 +/- 0.75 (0.86)	2.03 +/- 0.91 (0.83)	2.03 +/- 0.87 (0.85)
Methanol (CH3OH), ppbv	1.32 +/- 0.75	0.85 +/- 0.74	2.01 +/- 1.14	2.21 +/- 1.02	5.55 +/- 2.14
Ethanol (C2H5OH), pptv	96 +/- 74	75 +/- 71	164 +/- 110	156 +/- 106	322 +/- 161
CH4, ppbv	1791 +/- 16	1757 +/- 34	1794 +/- 20	1815 +/- 13	1819 +/- 24
CFC-12, pptv	538 +/- 3	526 +/- 9	538 +/- 3	538 +/- 3	538 +/- 4
CFC-11, pptv	254 +/- 2	243 +/- 7	254 +/- 2	254 +/- 2	252 +/- 2
CFC-113, pptv	78.4 +/- 0.6	75.8 +/- 1.7	78.5 +/- 0.8	78.4 +/- 0.5	78.5 +/- 0.5
H-1211, pptv	4.32 +/- 0.11	4.06 +/- 0.21	4.36 +/- 0.10	4.34 +/- 0.09	4.31 +/- 0.08
7Be, fCi/m3	500 +/- 680	2990 +/- 1750	370 +/- 510	760 +/- 780	640 +/- 550
Nitrate (NO3-), pptv	30 +/- 50	20 +/- 20	30 +/- 30	40 +/- 40	500 +/- 590
Sulfate (SO42-), pptv	60 +/- 40 (50)	100 +/- 40 (72)	70 +/- 50 (40)	110 +/- 60 (81)	290 +/- 260 (87)
Oxalate (C2O42-), pptv	6 +/- 5	8 +/- 4	6 +/- 4	15 +/- 7	114 +/- 131
Ammonium (NH4+), pptv	70 +/- 60 (121)	100 +/- 70 (170)	60 +/- 50 (101)	130 +/- 60 (230)	1270 +/- 1430 (324)
Sodium (Na+), pptv	110 +/- 180	90 +/- 110	80 +/- 80	130 +/- 340	100 +/- 100
Potassium (K+), pptv	30 +/- 40	30 +/- 70	30 +/- 30	20 +/- 20	170 +/- 160
Magnesium (Mg2+), pptv	7 +/- 9	5 +/- 6	5 +/- 5	11 +/- 16	10  +/- 14
Calcium (Ca2+), pptv	22 +/- 33	15 +/- 16	26 +/- 35	31 +/- 46	21 +/- 33
Fine sulfate aerosols, pptv	80 +/- 110	70 +/- 60	50 +/- 40	90 +/- 70	170 +/- 110
Modeled Asian CO, ppbv	16 +/- 8	20 +/- 5	16 +/- 7	27 +/- 6	21 +/- 2
Modeled NABB CO,f ppbv	3 +/- 2	3 +/- 2	2 +/- 2	4 +/- 3	28 +/- 29

aFor each type of air mass we indicate the observed mean+/-standard deviation (sigma). The mean model results sampled along the flight track are given in parenthesis. Chemical species that are significantly enhanced (&gt; mean + 1sigma) or depleted (< mean ­ 1sigma) with respect to background are highlighted in bold.
bNitrogen oxides, NOx = observed NO2 + observed NO.
cMeasurements of total peroxynitrates, SigmaPNs equiv N2O5 + HNO4 + PAN + PPN+ other organic peroxynitrates.
dWe define total reactive nitrogen, NOy, as the sum of observed NO + NO2 + PAN + HNO3 + HNO4.
eNA, not available.
fModeled North American biomass burning (NABB) CO.